Means for forming coil springs



Dec. 8, 1931. A. R. BOND 1,335,589

MEANS FOR FORMING COIL SPRINGS Filed April 9, 1929 NVENTOR TTORNE y Patented 1931 UNITED STATES l PATENT orr ce ALEXANDER RUSSELL BOITD, PLAIN FIELD,

AUTOMATIC SPRING- MACHIHTERY GOMJPAN Y, A CORPORATION OF OHIO m8 FOR FORMINGCOIL SPEINGS Application filed April a, 1929. Serial No. 353349.

My invention relates to improvements in means for forming coil springs.

spring ends will must be cut oil after the clip has been applied The invention relates more specifically to the forming'of .coil springs of uniform angular length, i. e. springs whose opposite'ends, regardless of vvariations in diameter of' the spring coils, will always bear a uniform angular relation to each other.

The "invention is particularly adapted for the forming of coil springs to bev used in spring structures for cushions, seats, mattresses and the like.

Formerly, it wasthe practise to knot the ends of such springs; in otherwords, each spring end was wrapped around an adj acent part of the spring so that the spring was formed with a closed coil at each end. .Re-

-cently, it has been found desirable to for spring structures in which the springs were provided with open end coils, each free spring end being connected by a metal clip to an adjacent spring. An advantage of this arrangement is that it gives greater flexibility to the spring structure, particularly where a hinged joint is provided between the clip and one of'the coils. pliedby hand or by machine, as special ma,- chines have been provided to perform the clipping operation.

One of the difiiculties encountered in making such spring structures is that springs, as heretofore made, vary considerably as to the angular relation to each other of.the opposite ends of each spring. Usually, it is desirable to have a clip at one end of the spring disposed in the same plane as that at the other end or else at an angle of 180 degrees thereto.

If the spring is to be connected to more than two adjacent springs the angular relation between the opposite spring ends may be correspondingly varied, but in any case there must be a fixed predetermined angular relation between the'spring ends to which the clips are afiixed. If this angular relation exceeds a predetermined amount, one of the project from the clip and to prevent the projecting end from piercing or tearing the padding or covering placed over the springs and also to prevent it from The clips may be ap-- has been the practiseto make the springs structures when a number of the structures are packed together for shipment. On the other hand, if-the angular relation is less than the predetermined amount, the spring must be stressed to bring both spring ends into proper alinement with the adjacent spring to which they are to be connected, and this results in warping or twisting of the spring structure. Furthermore such stressing of the springs can only be done by hand and if the clips are applied by machlne, after one spring end has been clipped the opposite spring end will fall short of the clipping mechanism. To overcome the possibility of failure to clip both ends of each spring, it a little longer than required so that there will always be a. spring end in position to be clipped and after the clipping operation the surplus wire projecting from the clip is cut oil or bent inward. I This procedure entails considerable waste of s ring stock, and loss of time in cutting ofiztlie spring ends after the clipping has beencompleted.

I am aware that efforts have been made to NEW JERSEY, Assmnoa' are m owmr springs of uniform dimensions so that the opposite spring ends would always bear a redetermlned angular relation. These eforts have been based on the theory that the angular variation of the spring ends is due.

to slippageof stock in the bending rolls of the coder, it being thought that if a definite length of wire were fed for each spring, the

resulting springs would be uniform. However, the difliculty but also in metallurgical variations of the spring stock. Two pieces ofwire of exactly the same length and run through. the same greater than that of the other. The more,

other wire and the resultant coils will be coiler will not produce springs that are exactly alike if the elasticity of one' wire is elastic wire will not be bent as much as the slightly larger. The variations in diameter of the coils might be inappreciable, but the variation in angular relation of the spring ends wbuld be considerable because it would be affected by-the average variation of cirlies not only in slippage.

cumference of the spring coils, multiplied by the number of the coils.

It is an object of my invention to overcome the dificulty not by measurin the length of the wire that is fed throng?) the coiler, but by measuring the spring after it has been coiled and cutting oii" the spring from the wire stock after the tree end of may be accomplished, aside from that shown of a length of wire mally clear of the spring.

in the particular embodiment illustrated.

In the drawing, the s ring coiler is indicated diagrammatically by a set of grooved rollers 1, 2 and 3 which bear on opposite sides 4: producing a bend in the wire. The wire is ted through the bending rollers in any well known manner and the relative osition of the rollers may be varied during t e feed of the wire therethrough so as to produce a springlof hour glass form, such as illustrated, or t ey may be held in fixed position so as to produce a cylindrical spring. Other variations may also be provided to produce special forms of springs, all of which are well known in the art and hence need no special descri tion here. As the spring stock 4 passes through the rollers 1, 2 and 3, it is bent into a coil spring 5. At a suitable point below the bending rollers, I provide a guide 6 having a flaring mouth into which the free end 7 of the spring 5 will enter after a predetermined number of coils have been formed in the spring. The uide 6 is made of hard rubber or other suitable insulating material and terminates in a contact block 8 of conducting material. The block 8 is connected by a wire 9 to one terminal of a battery 10 or other source of electrical energy, While the other terminal of the battery is connected by a line'll to one of the bendin rollers. Inserted in the line 11 is a solenoi 12 provided with-a plunger 13. Secured to the plunger and magnetically insulated therefrom by a spacer 140i bronze or other suitable non-magnetic material, isa cutter 15 which coacts with an anvil 16 ad jacent the bending rollers to sever the spring 5 from the spring stock 4. A spring 17 on the solenoid bears against a pin'18 on the spacer 14 and serves to hold the cutter nor- =In operation, as the wire is fed through the bending rollers and over the anvil 16 it will continue to be coiled freely until the freeruesasee end 7 enters the guide 6 and is guided thereby against the block 8. As soon as the wire end 7 makes contact with the block 8, the circuit of the battery will be completed by 'way of the coil 5 through the solenoid 12, and the cutter 15 will then be actuated to sever the spring 5 from the wire stock 4;. As soon as the spring 5 is cut 0d it will drop breaking the circuit of the solenoid l2 and the cutter will be retracted by a spring 17. In the meantime, the wire 4.- will continue to feed through the bending rollers and another sprin will be formed, only to be cut off when the rree end thereof engages the block 8. It will be evident that by this means all the coils produced by the coiler will be uniform in respect to the angular relation of their opposite ends, regardless of slippage or oi metallurgical variations in the spring stock. As shown in the drawing, the spring ends are disposed at an angle of 180 degrees to each other, plus an overlap equal to the width of the clip that is to be applied. This angular relation may be varied as desired by varying the angular position of: the block 8 with respect to the cutter 15. The linear distancebetween the block and cutter may also be varied for longer or shorter springs and the block 8 will have to be adjusted radially with respect to the axis of the spring for coils that vary considerably in diameter.

It will be understood that the mechanism as here illustrated is largely dia animatical and that many variations may e made in its form, so as to adapt the process to spring coilers of different t pes. Other well known forms of wire ben ing means may be employed. instead of using electrical energy to operate the cutter 13, it will be evident that the electrical energy may be employed to initiate the operation of a standard cut ofi mechanism. Thus my invention is not limited to the specific embodiment illustrated, but includes such variations as fall within the spirit and scopeof the appended claims.

I claim:

1, In a spring coiler, bendin tween which spring stock is to coil spring, a cutter for severing the spring from the stock, an electric circuit having one terminus thereof connected to the spring, a contact block connected to the other terminus of the circuit, said block being fixed in the path of the free end of the spring whereby said spring after being fed through a predetermined orbit will strike the block and close said circuit, and means actuated by closure of said circuit for operating the cutter to sever the spring from said stock.

2. In a spring coiler, bending rollers between which spring stock is fed to form a coil spring, a cutter rollers befor severing the spring from the stock, an electric circuit having one terminus thereof connected to the spring, a contact block connected to the other terminus to form a a of the circuit, said block being fixed in the path of the free end of the spring whereby the spring end after being fed toa predetermined extent will strike the block and complete said circuit, Ineans for guiding said free end to said block, and means actuated by closure of the circuit for operating the cutter to sever the spring from said stock.

In testimony whereof, I have signed this w specification.

ALEXANDER RUSSELL BOND. 

